Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacology > Nucleic Acid Inhibitors > Flashcards

Nucleic Acid Inhibitors Flashcards

1
Q

Which are the Fuoroquinolones

A

Ciprofloxacin
Levofloxacin
Gemifloxacin
Monifloxacin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Fluoroquinolones are derived from

A

Nalidixic Acid which is the Quinolone Mother Substance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Spectrum/Uses of Ciprofloxacin

A

Narrow spectrum
Potent activity against Gram-negative aerobic organisms
Enterococci
Pseudomonas Aeruginosa
Haemophilus
Neisseria
Legionelle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Ciprofloxacin is used for

A

DOC for Typhoid fever
Cystitis
Meningococcal Prophylaxis
LRT Infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is Ciprofloxacin not used for

A

Gram +ive bacteria (Streptococci and Pnemococci)
Anaerobic bacteria
Gonorrhoea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Spectrum/Uses of Moxifloxacin, Gemifloxacin and Levofloxacin

A

Active against Gram +ive
LRTis
Acute sinusitis
Skin infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Levofloxacin is used to treat

A

UTI
Soft tissue infections
M.Tuberculosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Moxifloxacin is used to treat

A

M.Tuberculosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

When are Moxifloxacin, Gemifloxacin and Levofloxacin used to treat Respiratory infections

A

In cases of B-Lactam allergy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Spectrum/uses of Norfloxacin

A

Only used in UTIs
Wider spectrum
Structurally similar to Nalidixic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Spectrum/Uses of Nalidixic acid

A

Very narrow spectrum of activity
Gram -ive bacteria: acute and chronic LUTIs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What can the use of Nalidixic Acid result in

A

Quinolone resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why is Nalidixic acid only indicated for LUTIs

A

Because it doesn’t achieve sustemic antibacterial levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

MOA of Fluoroquinolones

A
  1. Inhibit Topoisomerase II (DNA Gyrase)
  2. Inhibit Topoisomerase IV
    Bactericidal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Inhibition of Topoisomerase II causes

A

-It prevents the relaxation of +ively supercoiled DNA required for normal transcription and replication
-it also inhibits the cutting and joining action of the enzyme on DNA double helix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Inhibition of Topoisomerase IV causes

A

-It prevents the removal of supercoils by the enzyme
-it interferes with separation of replicated chromosomal DNA into respective daughter cells during cell division

17
Q

Resistance Mechanism against Fluoroquinolones

A
  1. One or more point mutation in Quinolone binding region of target enzyme
  2. Change in permeability
18
Q

How are Fluoroquinolones administered

A

Orally or IV
Best taken on empty stomach: 1-2hrs before or 2-3hrs after
Adequate fluid must be taken

19
Q

Absorption of Fluoroquinolones are impaired by what?

A

by divalent cations (antacids, milk, yogurt)
Causes formation of a chelate

20
Q

Why is adequate fluid intake needed for Fluoroquinolones?

A

it will prevent their crystallisation in urine

21
Q

What should be avoided when taking Quinolones

A

excessive urine alkalinity becos the drugs would then precipitate in the urine and form crystal urea.

22
Q

PK of Fluoroquinolones

A

Metabolized by CYP450 enzyme and some of them actually do inhibit this enzyme (Ciprofloxacin and Levofloxacin to a lower extent)

23
Q

SEs of Fluroquinolones

A

GIT disturbances and skin rashes
Seizure risk (exp. Ciprofloxacin)
Hallucinations (rare but in elderly)
Hyperglycaemia in diabteics
Hypoglycameia Type 2 diabetics who are receiving oral hypoglycemic agents
Damage to Growing cartilage and cause arthropathy+arthralgia
Incr. risk of Tendonitis and tendon rupture
Peripheral Neuropathy with incr. time of exposure
Photosensitivity
Rarely aortic aneurysm

24
Q

SEs of Nalidixic acid

A

Neurotoxic
Cause Photosensitivity
Could cause seizures

25
Q

Caution for Nalidixic acid

A

Elderly as it causes Neurotoxicity

26
Q

DIS of Fluoroquinolones

A

Ciprofloxacin+ theophylline
Warfarin+ Ciprofloxacin
NSAIDs: lower seizure threshold= increase. risk of seizures
Oral hypoglycemic agents: gibenclamide
Cipro+Levo may interfere with agents that prolong QT interval
Antacids/minerals
Probencid

27
Q

Cautions/CIs of Fluroqionolones

A

Epilepsy (Nalidixic acid CI)
Hepatic failure
Pregnancy/lactation
Babies/children <18yrs
Renal Failure (Nalidixic acid)
Porphyria (Nalidixic acid)
Elderly patients
allergy
G6PD deficiency

28
Q

Spectrum of Metronidazole

A

powerful antibacterial action against Anaerobic Organisms
Bactericidal
Antiprotozoal action on trophozoites

29
Q

Uses of Metronidazole

A

H.Pylori (PPI+amoxicillin+metronidazole)
Giardiasis: parasitic infection
Acute necrotizing Ulcerative gingivitis
Pseudomembranous colitis
Topical for Rosacea and bacterial vaginosis

30
Q

MOA of Metronidazole

A

Undergoes reduction steps to form reactive intermediates
These intermediates then react with DNA like macromolecules and cause:
-Alterations in DNA Helix
-Breaking of DNA chain

31
Q

Resistance mechanisms against Metronidazole

A

Decreased uptake
increased removal
decreased activation in bacteria
Altered enzymes that convert active metronidazole to non-toxic derivatives

32
Q

Admin of Metronidazole

A

Orally with water=near total ansorp.
Rectal, IV and Topically

33
Q

PK of Metronidazole

A

metabolised in liver
10-20 excreted unchanged in urine

34
Q

SEs of Metronidazole

A

Nausea, headache, dry mouth
Metallic taste
Mild GIT discomfort
Inhibits alcohol metabolism–> acetaldehyde dehydrogenase inhibited=acetaldehyde accumulates= Disulfiram-like effect
CNS effects
Possible dark colored urine

35
Q

Additional SEs of Metronidazole in Older patients

A

Blood counts when used long-term
History of Blood Dyscrasias

36
Q

DIs of Metronidazole

A

Cimetidine: M. metabolism decr.
Phenobarbitone: M. metabolism incr.
Phenytoin: M. metabolism decr.
Warfarin: anticoagulant effect incr= incr. risk of bleeding
Alcohol: decreased metabolism
Lithium: plasma levels incr.=toxicity
Disulfiram

37
Q

CI of Metronidazole

A

Alcohol use

38
Q

Caution with Metronidazole

A

Epilepsy
Porphyria
CNS disease
Impaired hepatic function
1st Trimester of pregnancy (can be used in other trimesters)
Lactation

Pharmacology (50 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions